The term “roof cladding sheets” is understood herein to mean sheets that include one or more parallel ribs with opposed sides, pan sections, and side edge formations that enable the sheets to be positioned side by side in overlapping relationship. Roof cladding sheets may be roll-formed from painted or unpainted steel strip or formed from extruded aluminium or plastics material.
It is known to secure roof cladding sheets to an underlying roof support structure, such as roof purlins, by fastening the sheets directly to the underlying structure using fasteners, such as roofing nails and screws, which pierce the sheets and penetrate the underlying structure. These sheets are commonly referred to as “pierce-fixed” sheets.
It is also known to secure roof cladding sheets to an underlying structure by using clips that are secured to the structure by fasteners and are formed to extend into the ribs of the sheets and include retaining members or tabs that can engage re-entrant portions of the ribs and thereby retain the sheets to the clips. These clips are often preferred because they enable concealed fixing of cladding sheets to an underlying structure. Roof cladding sheets that are secured via these concealed fixing clips are preferable to pierce-fixed sheets in situations where there is a need for improved aesthetics, improved weather resistance, improved security, and greater sheet lengths without end jointing by allowing thermal movement to occur between the roof cladding sheets and the clips. The Lysaght Klip-Lok (Registered Trade Mark) 700HS type roof cladding sheet is an example of one type of roof cladding sheet that is suitable for use with these concealed fixing clips.
In use, the concealed fixing retaining clips are secured to an underlying structure at spaced intervals related to the spacing between the ribs of the cladding sheets. Thereafter, roof cladding sheets are positioned on the clips in overlapping side by side relationship by successively pressing the sheets down onto the clips so that the sides of the ribs are initially forced outwardly to allow the re-entrant portions of the ribs to pass over the retaining members and then snap inwardly into engagement with the retaining members.
The installation of roof cladding sheets to form a roof involves the placement of sheets in side by side overlapping relationship across a section of the roof and in end to end relationship along the length of the roof in situations where roof cladding sheets are not sufficiently long and wide to cover a required roof area.
The present invention is concerned with holding roof cladding sheets in end to end relationship on a roof in a way that locates sheets securely on the roof and provides an effective weather seal.
The above references to the background art do not constitute an admission that the art forms a part of the common general knowledge of a person of ordinary skill in the art. The above references are also not intended to limit the application of the end lap system and components of the end lap system as disclosed herein.